/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.ignite.configuration.annotation;

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * This annotation can only be applied to a class that is either marked with {@link ConfigurationRoot} or the superclass is marked with
 * {@link ConfigurationRoot}, {@link Config}.
 *
 * <p>It indicates that this is a configuration extension that is used to enrich another {@link ConfigurationRoot} or {@link Config}
 * with more parameters. Can be used from a different module.
 * Any extensions are allowed for any configuration.
 *
 * <p>NOTE: Field name collisions are not allowed.
 *
 * @see ConfigurationRoot
 * @see Config
 */
@Target(TYPE)
@Retention(RUNTIME)
@Documented
public @interface ConfigurationExtension {
    /**
     * Controls whether this configuration is part of the public configuration or is hidden from the end user.
     * An extension is public by default.
     */
    boolean internal() default false;
}
